miteflea

Ear Mites and Other Mite Infections Ear mites -- Otic Scabies Infection (Otodectic Mange, Notoedric Mange) of Cats and Dogs

Treatment -- Chlorbenside (Mitox®) -- an insecticidal agent that is no longer available.

Rotenone ((Mitaplex-R®) -- Rotenone is a naturally occurring insecticide that exerts its action by uncoupling oxidative phosphorylation, specifically by inhibiting electron generation from NADH. Mitaplex-R® is applied in a manner similar to Mita-Clear® every other day until the infection has cleared. Noticeable improvement is usually seen after the second application, although additional treatments may be required to cure the infection. Overdoses and systemic absorption of rotenone generally causes CNS excitation and convulsions proceeding to CNS depression.

Mite Infestation of Birds
Avian mite infection can be relatively common. Treatment is with a pyrethrin spray (Mite & Lice Spray). Remove food and water from the cage and lightly spray the bird (in its cage) with 3-4 pumps of the sprayer, avoiding the face and eyes. Treatment should be continued twice weekly until the infection has cleared, cleaning the cage thoroughly once weekly to avoid re-infestation.

Canine Scabies (Sarcoptic Mange)
This infection of dogs is analogous to human scabies infections. In dogs it produces papular eruptions; thick, scaly skin; crusts; and alopecia, especially of the elbows, ear margins, hocks, legs, chest, and ventral abdomen, before becoming generalised. Animals generally respond well to treatment.

Amitraz (Mitoban®) -- an insecticide that acts as an octopamine agonist (octopamine is the adrenergic neurotransmitter in arthropods -- thus, amitraz causes excess adrenergic activity in the mite). NOTE that in mammals, amitraz acts as an alpha-2 agonist, thus the side effects observed in dogs relate to this action and include sedation, bradycardia, hypotension, hyperglycæmia, and gastrointestinal stasis. It is applied every 2 weeks for three treatments. Amitraz is extremely toxic to cats and "toy" dogs and should not be used on these animals. It is also flammable until it has been mixed with water, so due care should be taken with the product. One bottle (10.6 ml) is mixed with 2 gallons of water and applied to the animal. Fresh solutions should be made for each application.

Lime Sulphur (Calcium polysulphide) is an older treatment that is still moderately successful in treating sarcoptic mange. A 1:30 solution of 2% lime sulphur is applied every 5 days for 6-8 treatments. The mechanism of scabicidal action is not known.

The use of home remedies such as kerosene, gasoline, used motor oil, or creosote dips should be discouraged, since the risk of animal harm outweighs any beneficial effect.

An alternative therapy to application of the above medications is ivermectin, administered in a dose of 200 mcg/Kg subcutaneously, with a second dose in 2 weeks.

Demodectic Mange
Demodectic mange typically responds very poorly to treatment. This is often complicated by an accompanying decrease in the immune response of the infected animal. It most often affects dogs (especially young dogs) although cats may also be infected. In dogs it generally presents as alopecia, erythema, pustular eruptions, and scales along the head and extremities. The lesions may become generalised, especially in Dalmatians, English bulldogs, Chinese Shar-peis, Old English sheepdogs, Great Danes, and boxers. There appears to be a hereditary disposition for the disease (especially in the above species). Infection may require monthly treatment. In cats, infection presents as primarily local areas affecting the eyes, ears, head, and neck. If feline demodectic mange becomes generalised, it probably represents an underlying disease such as feline leukæmia viral infection, diabetes mellitus, systemic lupus erythematosus, or cancer.

Amitraz -- If demodectic mange becomes generalised, it may be treated with amitraz dips as described above for sarcoptic mange EXCEPT treatment is weekly for 6 weeks and again 2 weeks after negative scrapings for the mite have been seen.

Fenchlorphos (Ronnel®) -- an organophosphate insecticide that is applied to no more than 1/3 of the body area on a rotating basis daily. (For example, the head, shoulders, and forelegs Monday, the trunk/abdomen Tuesday, and the hindquarters/back legs on Wednesday)

Feline demodectic mange is most often treated with rotenone and lime sulphur.

Flea Control In addition to the obvious annoyance factor associated with fleas, they may also cause secondary infections (which may arise from the transmission of a disease causing organism from the flea itself or which may occur as a secondary infection caused by the animal's scratching from the flea infestation). Moreover, many animals may exhibit a flea allergy dermatitis that can be life-threatening. Therefore, successful control of flea infestation is of primary concern for many pet owners.

Subject with FAD. Note the anorexic, Subject following recovering from FAD. Note

appearence and caudal alopecia. The the healthy appearence of the coat. The

subject weight was approximately 4.5 Kg. subjects weight returned to 9 Kg.

Diagnosis -- Positive diagnosis is usually based upon the initial clinical findings discussed above and antigen testing specific for flea allergy dermatitis.

Specific treatment for FAD -- In addition to eradication of fleas from the pet, symptomatic treatment is often required for FAD. (NOTE that symptomatic treatment may be required PRIOR to whole body treatment for flea infestation, since open wounds may increase the absorption of the insecticide by the pet, thus increasing the likelihood of toxicity.)

Superficial pyoderma and infection -- weekly baths with an antibacterial shampoo (Nolvosan®, chlorhexidine or Pyoben®, benzoyl peroxide). Courses of oral antibiotics (amoxicillin is commonly used) may also be required for up to three weeks.

Pruritus and Inflammation --

Prednisolone or prednisone (0.55 mg/Kg q12h for 5 days, q24h for 5 days, then q48h for 10 days) -- should not generally be used until the infection has been controlled, due to the immunosuppressive effects of the drug.

Indoor Treatment -- The pet's local environment (bedding, carpet, et c.) should be thoroughly cleaned. Adult fleas should be exterminated through the use of an adulticide such as chlorpyrifos or the pyrethroids ("foggers" and similar insecticides are generally good initial products for this phase of flea control). Growth inhibitors (methoprene, fenoxycarb) should then be applied to bedding, carpets, and any other areas that fleas may inhabit. These treatments should be applied every 2 weeks for 1 month and then every month or two throughout the flea season.

Pet Treatment -- Actively infected animals should be treated with weekly dips of organophosphate or pyrethroid insecticides. (Note that these may be toxic to the pet if sufficient insecticide is absorbed -- the pet should have no open wounds and exposure should be limited to the minimum required for flea extermination.) The pet should also be sprayed with a pyrethroid spray daily or every other day between dips. Flea shampoos are rarely effective, since they do not persist on the pet for a sufficient period. The pets should also be placed on long-term therapy designed to prevent future flea infestation.

Lufenuron (Program®) -- Lufenuron inhibits chitin synthesis, thus inhibiting the formation of egg shells in forming fleas and inhibiting exoskeleton formation in maturing fleas. It produces few side effects in the pet. It is administered orally in dogs and cats 6 weeks old or older. Dosage is one (1) tablet monthly. It may be used in greyhounds and in pets that are pregnant or lactating. Its efficacy is greatest in younger and maturing fleas (not as effective in mature fleas). A six-month depot injection has also been developed for use in cats. It should not be used in dogs, due to a higher incidence of adverse reactions.

Imidacloprid (Advantage®) -- Imidacloprid binds to the niconyl receptor located post-synaptically on the adult flea nerve, thus inhibiting nicotinic cholinergic-like action in the flea. Nicotinic antagonist action is not observed in the pet, since the binding sites are sufficiently different to preclude substantial binding and since imidacloprid is administered locally, and systemic absorption is limited. The dose is predetermined, based upon the animals weight (10 mg/Kg). The dose is administered to the area between the animal's shoulder blades. It then becomes distributed over the body surface of the pet. Imidacloprid will persist on the pet for at least one (1) month (dosing is recommended on a monthly basis) or longer. Washing or becoming wet does not wash the medication off nor does it inhibit its efficacy. Clinical trials indicate that a 90% flea kill is achieved within 8 hours of the initial dosing with a 98-100% kill rate within 24 hours.

Cyromazine (used primarily with poultry to control maggot population), Fenoxycarb (Americare Advanced Indoor Flea Spray®), Methoprene (Ovitrol® Flea collars for cats and dogs, Siphotrol Spray) -- These agents mimic the juvenile hormone of insects, prolonging the larval stage, thus inhibiting the maturation and development of the insect. Applications may be effective for up to 21 weeks.

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